Polyolefin bound ultraviolet light absorbers

ABSTRACT

Oligomeric materials contain ultraviolet light absorbing compounds that are covalently bound to the oligomer backbone through an ester or amide linkage. These ultraviolet light absorbing oligomers may be combined with polymers such as polyolefins to provide protection against the harmful effects of ultraviolet light.

FIELD OF THE INVENTION

[0001] This invention relates to oligomers that contain ultravioletlight absorbing compounds (UVAs) covalently bound to the oligomericbackbone. The invention also relates to stabilization of polymers orother substrates against photochemical degradation by use of theoligomers.

BACKGROUND OF THE INVENTION

[0002] Many plastics tend to degrade when exposed to sunlight or othersources of ultraviolet (UV) light. This exposure results in, forexample, loss of tensile strength, embrittlement, and discoloration. Tohelp prevent such degradation, ultraviolet light stabilizers are oftenincorporated into a polymer composition, which is used as a protectivetop layer for underlying materials. These uv light stabilizers performwell but are often not stable in or compatible with the polymer, whichresults in the stabilizer leaving the polymer by leaching, migration,vaporization, or other means. When the uv stabilizer levels are loweredin this manner, their protective effect is diminished, leading todegradation of the polymer and the underlying materials.

[0003] Molecules that function as ultraviolet light absorbers aregenerally known in the art. For example, in U.S. Pat. No. 4,853,471 Rodyet al. describe 2-(2-hydroxyphenyl)-benzotriazole compounds that areuseful as ultraviolet light absorbers. These compounds are described asuseful in the stabilization of a wide variety of polymeric materialsagainst ultraviolet light, particularly those that are used in thepreparation of photographic materials. Other classes of ultravioletlight absorbers include the 2-hydroxybenzophenones and thediphenylcyanoacrylates.

[0004] While such compounds are known to absorb ultraviolet light, theirincompatibility with the polyolefins often used as the top film inmultilayer sheetings has limited their usefulness in such constructions.The low solubility and high mobility of typical ultraviolet lightabsorbers in polyolefins results in an inability to maintain high levelsof these compounds in polyolefin films; the compounds tend to bloom ormigrate out of the film, and the protective properties of the compoundsare lost.

[0005] Much effort has been directed to the development of methods ofmaintaining the uv stabilizer compound in a selected polymeric matrix.Ultraviolet light stabilizers have been developed that havepolymerizable functionalities. The polymerizable stabilizer is thenincorporated into the polymer as a co-monomer or copolymerized withanother monomer to form a stabilizing polymer that can be added to thedesired polymer. Because the stabilizing compound is then part of thepolymer backbone, it remains in the polymer composition and thestabilizing benefits are retained for a longer period of time. Examplesof incorporation of a stabilizing monomer into a polymer backbone may befound in, for example, Vogl et al., POLYMER, Vol. 26, p. 1288 (1985);U.S. Pat. Nos. 3,313,866 (Horton et al.), 4,128,536 (Brodsky et al.),and 4,528,311 (Beard et al.).

[0006] There has also been development in the area of “attaching” theultraviolet light absorbing compound to a polymer backbone by selectingUV light absorbers with groups that react with various functionalitiespresent on the polymer. Fu et al., in U.S. Pat. No. 4,413,096, describeα-olefin copolymers wherein hindered amine light stabilizers are pendantto the polymer backbone. The Fu copolymers may be prepared bytransesterification of the polymer with the hindered amine lightstabilizing compound.

[0007] There is a continuing need in the art for a method of stabilizingpolymers such as polyolefins with ultraviolet light absorbing compoundsthat provides lasting protection both to the polyolefin and to articlesthat incorporate the polyolefin.

SUMMARY OF THE INVENTION

[0008] We have found that hydroxy or amine functional ultraviolet lightabsorbing compounds may be covalently bound to a carboxyl functionaloligomer. This covalent bonding allows us to deliver a compatiblenon-fugitive uv absorber to polyolefin type polymers. Accordingly, theinvention provides an ultraviolet light absorbing oligomer made up of anultraviolet light absorbing oligomer comprising the reaction product ofa carboxyl functional oligomer and a hydroxy or amine functionalultraviolet light absorbing compound, wherein the ultraviolet lightabsorbing compound is a group of formula (I), (II), (III), or (IV):

[0009] wherein each R1 is independently halogen, hydroxy, straight-chainor branched C₁₋₁₂ alkyl, straight-chain or branched C₂₋₁₂ alkenyl,straight-chain or branched C₁₋₁₂ alkoxy, straight-chain or branchedC₂₋₁₂ alkenyloxy, straight-chain or branched C₁₋₁₂ alkanol, amino,straight-chain or branched C₁₋₁₂ alkylamino, or straight-chain orbranched C₁₋₁₂ dialkylamino; Y is a C₁₋₁₈ alkylene or C₂₋₁₈ alkenylenegroup which may be straight-chain or branched and which may beinterrupted by one or more

[0010] wherein each R2 is independently H or C₁₋₆ alkyl that may bestraight-chain or branched; and Z is —OH or —NH₂.

[0011] The invention also provides polymer compositions that contain theUV light absorbing oligomer and a polyolefin, and articles such asretroreflective sheetings, conformable pavement markers, and signs thatcontain films made of the polymer composition.

[0012] In one such aspect the invention provides a conformable markingsheet comprising a top polymeric film layer having glass microspheresand skid resistant particles partially embedded therein, the filmcomprising a polyolefin and the ultraviolet light absorbing oligomer ofthe invention; a base layer comprising a deformable thermoplasticpolymer and a nonreinforcing mineral particulate; a pressure sensitiveadhesive layer; and a release liner.

[0013] In another aspect of the invention is provided an enclosed-lensretroreflective sheeting comprising a layer of lenses anchored in abinder layer, a specularly reflective layer underlying the lenses, and atop layer comprising a polymeric film, said film comprising a polyolefinand the ultraviolet light absorbing oligomer of the invention.

[0014] All percentages are weight percentages based on total compositionweight unless otherwise specified.

DETAILED DESCRIPTION OF THE INVENTION

[0015] The UV light absorbing oligomers of the invention are generallyprepared by reacting a carboxyl bearing oligomer with a hydroxy or aminefunctional ultraviolet light absorbing compound. The carboxyl functionaloligomer contains at least one monomer having a pendant carboxyl (—COOH)group. Carboxyl functional oligomers useful in the formation of the UVlight absorbing oligomers of the invention typically have a weightaverage molecular weight of about 100 to 10,000, preferably about 1000to 3500. The acid number (mg KOH required to neutralize 1 gram of theoligomer) of the oligomer is generally about 40 to 180.

[0016] Monomers useful in the formation of the carboxyl functionaloligomer include ethylenically unsaturated carboxylic acids. Thecarboxyl functional oligomer may be a homopolymer or copolymer of suchcarboxy bearing monomers. The copolymer may contain different carboxybearing monomers, or may contain a carboxy bearing monomer and anon-carboxy bearing monomer. Examples of useful types of non-carboxybearing monomers include ethylenically unsaturated carboxylic acidesters, olefins, vinyl compounds, and the like.

[0017] Suitable ethylenically unsaturated carboxylic acids includealkenoic and aralkenoic mono- di- and tri-carboxylic acids having up to20 carbon atoms as well as acids having higher numbers of carboxylgroups. Examples of such acids include acrylic acid, methacrylic acid,fumaric acid, maleic acid, crotonic acid, itaconic acid and cinnamicacid. Of these, acrylic acid and methacrylic acid are preferred.

[0018] Comonomers that may be used in the preparation of the carboxylfunctional polymer include olefins such as ethylene, propylene, andbutylene; ethylenically unsaturated aromatic monomers that contain up to20 carbon atoms such as styrene and vinyl tolulene; ethylenicallyunsaturated esters of carboxylic acids that contain a total of up to 20carbon atoms such as vinyl acetate; and the like. Of these, the olefinsare a preferred class of comonomer, and ethylene is particularlypreferred.

[0019] The carboxyl functional oligomer may be an oligomer havingrandomly recurring structural units of the formula (V):

[0020] wherein R3 is H or C₁₋₁₈ alkyl which may be straight or branched;

[0021] each R5 is independently H or C₁₋₆ alkyl which may be straight orbranched; and a, b, and c are selected to provide a weight averagemolecular weight of about 100 to 10,000, provided that c is at leastone.

[0022] Ethylene-acrylic acid copolymer having a weight average molecularweight of about 1000 to 3500 is a particularly preferred carboxylfunctional oligomer. Commercially available examples of preferredethylene-acrylic acid copolymers include the A-C® copolymers availablefrom Allied Signal Inc., Morristown, N.J.

[0023] The carboxyl functional oligomer can be prepared usingpolymerization methods known in the art. See, for example, Knutson etal., U.S. Pat. No. 3,658,741, which is incorporated herein by reference.Detailed information on polymer and oligomer preparation may be found,for example, in the Encyclopedia of Polymer Science and Engineering,Vol. 6, Wiley & Sons 1986, pp. 383-429.

[0024] The carboxyl functional oligomer is reacted with one or morehydroxy or amine functional ultraviolet light absorbing compounds toproduce the UV light absorbing oligomer of the invention. In addition toabsorbing ultraviolet light, the ultraviolet light absorbing compoundsuseful in the invention are preferably transparent to visible light.Useful classes of hydroxy and amine functional ultraviolet lightabsorbing compounds include hydroxy and amine containing2-hydroxyphenylbenzotriazoles, 2-hydroxybenzophenones, anddiphenylcyanoacrylates.

[0025] Any 2-hydroxyphenylbenzotriazole ultraviolet light absorbingcompound that contains a terminal hydroxy or amine group may be used inthe material of the invention. Suitable 2-hydroxyphenylbenzotriazolecompounds include those having formula (I):

[0026] wherein each R1 is independently halogen, hydroxy, straight-chainor branched C₁₋₁₂ alkyl or C₂₋₁₂ alkenyl, straight-chain or branchedC₁₋₁₂ alkoxy, straight-chain or branched C₂₋₁₂ alkenyloxy,straight-chain or branched C₁₋₁₂ alkanol, amino, straight-chain orbranched C₁₋₁₂ alkylamino, or straight-chain or branched C₁₋₁₂dialkylamino; Y is a C₁₋₁₂ alkylene or C₂₋₁₂ alkenylene group that maybe straight or branched and that may be interrupted by one or more —O—,—C(O)—, —C(O)O—, —OC(O)—, —NR2—, —C(O)NR2—, or —NR2C(O) groups; and Z isOH or NH₂; and R2 is H or C₁₋₆ alkyl which may be straight or branched;

[0027] Of these, 2-hydroxyphenylbenzotriazole compounds having formula(Ia) are preferred:

[0028] wherein R6 is H or C₁₋₄ alkyl which may be straight or branched.

[0029] Another useful class of ultraviolet light absorbing compounds isthe 2-hydroxybenzophenones. So long as they contain a terminal hydroxyor amine group, any 2-hydroxybenzophenone ultraviolet light absorbingcompound may be used. Examples of 2-hydroxybenzophenone compounds thatmay be used in the invention include those of formula (II) and (III):

[0030] wherein each R1 is independently halogen, hydroxy, straight-chainor branched C₁₋₁₂ alkyl, straight-chain or branched C₂₋₁₂ alkenyl,straight-chain or branched C₁₋₁₂ alkoxy, straight-chain or branchedC₂₋₁₂ alkenyloxy, straight-chain or branched C₁₋₁₂ alkanol, amino,straight-chain or branched C₁₋₁₂ alkylamino, or straight-chain orbranched C₁₋₁₂ dialkylamino; Z is OH or NH₂; and Y is a C₁₋₁₂ alkyleneor alkenylene group that may be straight-chain or branched and that maybe interrupted by one or more —O—, —C(O)—, —C(O)O—, —OC(O)—, —NR2—,—C(O)NR2—, or —NR2C(O) groups wherein R2 is H or C₁₋₆ alkyl that may bestraight-chain or branched.

[0031] Examples of particular 2-hydroxybenzophenone compounds useful inthe invention include compounds of formulas (IIa) or (IIIa):

[0032] wherein the octyl group may be straight-chain or branched.

[0033] Diphenylcyanoacrylate ultraviolet light absorbing compounds mayalso be used, so long as they contain a terminal hydroxy or amine group.Examples of useful diphenylcyanoacrylate compounds include those offormula (IV):

[0034] wherein each R1 is independently halogen, hydroxy, straight-chainor branched C₁₋₁₂ alkyl, straight-chain or branched C₁₋₁₂ alkenyl,straight-chain or branched C₁₋₁₂ alkoxy, straight-chain or branchedC₁₋₁₂ alkenyloxy, straight-chain or branched C₁₋₁₂ alkanol, amino,straight-chain or branched C₁₋₁₂ alkylamino, or straight-chain orbranched C₁₋₁₂ dialkylamino; Z is OH or NH₂; and Y is a C₁₋₁₂ alkyleneor alkenylene group that may be straight or branched and that may beinterrupted by one or more —O—, —C(O)—, —C(O)O—, —OC(O)—, —NR2—,—C(O)NR2—, or —NR2C(O) groups; and R2 is H or C₁₋₆ alkyl which may bestraight-chain or branched.

[0035] Dimers of any of these ultraviolet light absorbing compounds canbe used as well.

[0036] Other ultraviolet light absorbing compounds may also be used,provided they contain a terminal hydroxy or amine group. Examples ofsuch compounds include p-hydroxybenzoates and triazines. The hydroxy oramine functional ultraviolet light containing compounds may be usedalone or in combination in the oligomers, materials and films of theinvention.

[0037] The UV light absorbing oligomers of the invention are prepared byreacting the carboxyl functional oligomer with the hydroxy or aminefunctional ultraviolet light absorbing compound. No solvent isnecessary, as the reaction may be carried out in the molten or liquidoligomer, but an organic solvent may be used if desired.

[0038] In general the reaction is carried out by combining the carboxylfunctional oligomer, the hydroxy or amide functional UV light absorbingcompound and an appropriate catalyst in a reaction vessel. The mixtureis heated with stirring until the oligomer melts. Stirring at anelevated temperature, e.g. 220-240° C. may be continued until nounreacted UVA remains. The reaction mixture is monitored by TLC (ThinLayer Chromatography) or other suitable means until the reaction isdetermined to be complete.

[0039] The carboxyl functional oligomer and the hydroxy or aminefunctional UV light absorbing compound are present in proportionsselected to provide the desired amount of UV light absorber loading inthe oligomer. Levels of about 2 to 25 wt-% based on the total oligomerweight are preferred, although higher or lower levels may be useddepending on the particular end use.

[0040] The reaction is carried out in the presence of an effectiveesterification catalyst, such as dibutyl tin oxide, dibutyl tinhydroxide, butyl tin oxide hydroxide, stannous octoate, lithiumricinoleate and bismuth neodecanoate. The preferred catalyst is butyltin oxide hydroxide (available as FASTCAT 4100 from Atochem NorthAmerica, Inc., Philadelphia, Pa.). The catalyst generally makes up about0.01 to 5.0 wt-% of the reaction mixture, preferably about 0.1 to 1.0wt-%, although slightly more or less may be required depending on theparticular catalyst employed.

[0041] The ultraviolet light absorbing oligomer thus formed may be usedas is or blended into polymers such as polyolefins which may be furtherprocessed as desired. For example, they may be formed into films thatare durable and provide protection to underlying substrates or materialsagainst the harmful effects of ultraviolet light.

[0042] The polymeric material of the invention is made by combining theultraviolet light absorbing oligomer of the invention with a polymersuch as a polyolefin. Because it is covalently bound to the oligomer,the ultraviolet light absorber does not bloom or migrate out of thepolymer, thereby increasing the useful life of articles that areconstructed using films made of the material.

[0043] Polyolefins that may be used in the polymeric material of theinvention include polymers that are made from at least one olefinicmonomer. Examples of such olefinic monomers include ethylene, propylene,butylene, styrene, and the like, with ethylene the preferred olefinicmonomer.

[0044] The polyolefin may be a homopolymer of the olefinic monomer, orit may be a copolymer of different olefinic monomers or of an olefinicmonomer and another monomer. The comonomer may be any monomer that canbe copolymerized with the olefinic monomer, so long as it does notresult in incompatibility with the UV light absorbing oligomer. Usefultypes of comonomers include ethylenically unsaturated carboxylic acids;ethylenically unsaturated carboxylic acid esters; and vinyl containingmonomers. The ethylenically unsaturated carboxylic acids are a preferredclass of comonomers, with acrylic acid especially preferred.

[0045] The polymeric material is prepared by combining the UV lightabsorbing oligomer of the invention with a polyolefin. The UV lightabsorbing oligomer is generally present in an amount high enough toprovide protection from ultraviolet light, but not so high that thematerial migrates, separates, or blooms out of the polyolefin. Typicallythe polymeric material contains a sufficient amount of the UV lightabsorbing oligomer to provide about 0.05 to 50 wt-%, preferably about 1to 20 wt-% of the ultraviolet light absorbing compound in the materialbased on the total material weight.

[0046] The polymeric material may be prepared by blending a melt of thepolyolefin with a melt of the UV light absorbing oligomer with stirringuntil the mixture is uniform. After uniformity is achieved, the mixturemay be pressed or formed into a film or other shape using methods knownin the art. The film may also be prepared by co-extruding the polyolefinpolymer and the UV light absorbing oligomer directly into a film.

[0047] Films containing the polymeric material of the invention may beused as the top layer or cover film of a multilayered retroreflectivesheeting. Retroreflective sheetings are generally known in the art, asseen for example in Bailey et al., U.S. Pat. No. 4,767,659, which isincorporated herein by reference. The polymeric films provide protectionto the lower layers of the sheeting from ultraviolet light, therebyextending the useful life of the sheeting and articles that incorporatethe sheeting.

[0048] In addition to providing protection from ultraviolet light, whenused as the top layer of a retroreflective sheeting, the polymeric filmshould be sufficiently extensible to withstand substantial stretchingsuch as the embossing of a license plate, sufficiently soft that itresists localized delamination when stretched to conform to an irregularsurface, and should have good impact resistance. Preferably, when usedas the top layer of a retroreflective sheeting the polymeric film has anelongation of at least about 100%, good impact resistance, toughness,and transparency.

[0049] Retroreflective sheetings that contain the polymeric film of theinvention as a top layer typically contain multiple layers. One exampleof a suitable retroreflective sheeting is a sheeting article thatcontains a binder layer; a layer of glass microspheres fully orpartially embedded in the binder layer; a specularly reflective layer;and an adhesive layer covered by a removable liner. Other layers may bepresent as desired.

[0050] To prepare a retroreflective sheeting using the polymeric film ofthe invention, the film is laminated to a retroreflecting base materialthat contains multiple layers as described above.

[0051] The retroreflective sheetings prepared using the polymeric filmof the invention may be applied to a wide variety of articles, includingtraffic signs, barriers, and cones, as well as embossed license orinformation plates. The preparation of embossed information plates isdescribed in U.S. Pat. Nos. 5,085,918 and 5,227,194, both of which areincorporated herein by reference.

[0052] The films of the invention may also be used in the preparation ofconformable pavement marking sheets. Such conformable marking sheets aredescribed in Lasch et al., U.S. Pat. No. 5,194,113, which isincorporated herein by reference.

[0053] When used in the preparation of a conformable marking sheet, thepolymeric film should be sufficiently ductile to allow the sheet toconform to the surface of the pavement or other substrate in order toimprove the adhesion of the sheet to the substrate. When used as a toplayer in a conformable marking sheet, the polymeric film preferablyincludes a visibility enhancing pigment such as titanium dioxide or leadchromate.

[0054] The polymeric film top sheet or layer may be extruded orlaminated directly onto the other layers of the conformable sheet, or anadhesive or other layer may be interposed between the top layer andother layers of the sheet.

[0055] The polymeric films of the invention may also be used as amarking sheet independent of a conforming layer. If used in this manner,the polymeric film may be laminated to a layer of pressure sensitiveadhesive to improve adhesion to the pavement or other substrate. Arelease liner may also be present to provide ease of handling andstorage. In addition, particles may be fully or partially embedded inthe top surface of the film to improve the retroreflectivity and/or skidresistance properties of the film.

[0056] The invention is further described by reference to the followingexamples, which are understood to be illustrative only and not limitingof the invention.

EXAMPLES Example 1

[0057] This example utilized Allied-Signal A-C 5120 oligomer, acopolymer of about 15% acrylic acid and 85% ethylene, having a weightaverage molecular weight of about 1500 and a carboxylic acid equivalentweight of about 475 and Uvinul® X-19, 2-hydroxy-4-(2-hydroxyethoxy)benzophenone, available from BASF Inc., Ludwigshafen, Germany.

[0058] To prepare the ultraviolet light absorbing oligomer, 25 g of A-C5120 was placed in a 100 ml, 3-necked round bottom flask. Ten grams ofthe Uvinul® X-19 and 0.008 g of Fastcat® 4100 butyl tin hydroxidecatalyst were added, without use of a solvent. The reaction mixture wasstirred and heated to 150° C., when a homogeneous melt was formed. Anitrogen sparge was added beneath the liquid level, heating wascontinued until the temperature reached 220° C., and the mixture washeld at 220-230° C., with stirring, for 4 hours. After 4 hours TLC (50%ethyl acetate/50% hexanes) showed little unreacted benzophenone. Themolten mixture was poured from the flask into an aluminum pan andallowed to cool to room temperature.

Example 2

[0059] Twenty-five grams of the product of Example 1 in pulverized formwas dry blended with 490 g of Primacor® 3440 (polyethylene-co-acrylicacid), available from Dow Chemical, Midland, Mich.). The blend wasextruded onto a polyester carrier as a nominal 2 mil (51 microns) film,and the temperature profile was Zone 1—350° F. (177° C.), Zone 2—380° F.(193° C.), Zone 3 and die—420° F. (216° C.). Melt temperature was 306°F. (152° C.). Extrusion took place on a Haake ¾″ single screw extruder.The UVA loading of the film was 1.2 wt-%.

[0060] The above specification, examples and data provide a completedescription of the manufacture and use of the composition of theinvention. Since many embodiments of the invention can be made withoutdeparting from the spirit and scope of the invention, the inventionresides in the claims hereinafter appended.

We claim:
 1. An ultraviolet light absorbing oligomer comprising thereaction product of a carboxyl functional oligomer and a hydroxy oramine functional ultraviolet light absorbing compound, wherein theultraviolet light absorbing compound is a group of formula (I), (II),(III), or (IV):

wherein each R1 is independently halogen, hydroxy, straight-chain orbranched C₁₋₁₂ alkyl, straight-chain or branched C₂₋₁₂ alkenyl,straight-chain or branched C₁₋₁₂ alkoxy, straight-chain or branchedC₂₋₁₂ alkenyloxy, straight-chain or branched C₁₋₁₂ alkanol, amino,straight-chain or branched C₁₋₁₂ alkylamino, or straight-chain orbranched C₁₋₁₂ dialkylamino; Y is a C₁₋₁₈ alkylene of C₂₋₁₈ alkenylenegroup which may be straight-chain or branched and which may beinterrupted by one or more

wherein each R2 is independently H or C₁₋₆ alkyl that may bestraight-chain or branched; and Z is —OH or —NH₂.
 2. The ultravioletlight absorbing oligomer of claim 1 wherein the group of formula (I),(II), (III), or (IV) comprises about 1 to 25 wt-% of the oligomer. 3.The ultraviolet light absorbing oligomer of claim 1 wherein at least oneultraviolet light absorbing compound is a group of formula (I).
 4. Theultraviolet light absorbing oligomer of claim 1 wherein at least oneultraviolet light absorbing compound is a group of formula (Ia):

wherein R6 is H or C₁₋₄ alkyl which may be straight or branched.
 5. Theultraviolet light absorbing oligomer of claim 1 wherein at least oneultraviolet light absorbing compound is a group of formula (II).
 6. Theultraviolet light absorbing oligomer of claim 1 wherein at least oneultraviolet light absorbing compound is a group of formula (III).
 7. Theultraviolet light absorbing oligomer of claim 1 wherein at least oneultraviolet light absorbing compound is a group of formula (IIa):


8. The ultraviolet light absorbing oligomer of claim 1 wherein at leastone ultraviolet light absorbing compound is a compound of formula (IV).9. A polymeric material comprising a polyolefin and an ultraviolet lightabsorbing oligomer, said ultraviolet light absorbing oligomer comprisingthe reaction product of a carboxyl functional oligomer and a hydroxy oramine functional ultraviolet light absorbing compound, wherein theultraviolet light absorbing compound is a group of formula (I), (II),(III), or (IV):

wherein each R1 is independently halogen, hydroxy, straight-chain orbranched C₁₋₁₂ alkyl, straight-chain or branched C₂₋₁₂ alkenyl,straight-chain or branched C₁₋₁₂ alkoxy, straight-chain or branchedC₂₋₁₂ alkenyloxy, straight-chain or branched C₁₋₁₂ alkanol, amino,straight-chain or branched C₂₋₁₂ alkylamino, or straight-chain orbranched C₁₋₁₂ dialkylamino; Y is a C₁₋₁₈ alkylene of C₂₋₁₈ alkenylenegroup which may be straight-chain or branched and which may beinterrupted by one or more

wherein each R2 is independently H or C₁₋₆ alkyl that may bestraight-chain or branched; and Z is —OH or —NH₂.
 10. The polymericmaterial of claim 9 wherein the polyolefin comprises an ethylene-acrylicacid copolymer.
 11. The polymeric material of claim 9 wherein at leastone ultraviolet light absorbing compound is a group of formula (I). 12.The polymeric material of claim 9 wherein at least one ultraviolet lightabsorbing compound is a group of formula (II).
 13. The polymericmaterial of claim 9 wherein at least one ultraviolet light absorbingcompound is a group of formula (III).
 14. The polymeric material ofclaim 9 wherein at least one ultraviolet light absorbing compound is agroup of formula (IV).
 15. A polymeric film comprising the polymericmaterial of claim 9 .
 16. A method of protecting a substrate from theeffects of ultraviolet light, the method comprising applying a polymericfilm to the substrate, said film comprising a polyolefin and thereaction product of a carboxyl functional oligomer and a hydroxy oramine functional ultraviolet light absorbing compound, wherein theultraviolet light absorbing compound is a group of formula (I), (II),(III), or (IV):

wherein each R1 is independently halogen, hydroxy, straight-chain orbranched C₁₋₁₂ alkyl, straight-chain or branched C₂₋₁₂ alkenyl,straight-chain or branched C₁₋₁₂ alkoxy, straight-chain or branchedC₂₋₁₂ alkenyloxy, straight-chain or branched C₁₋₁₂ alkanol, amino,straight-chain or branched C₁₋₁₂ alkylamino, or straight-chain orbranched C₁₋₁₂ dialkylamino; Y is a C₁₋₁₈ alkylene of C₂₋₁₈ alkenylenegroup which may be straight-chain or branched and which may beinterrupted by one or more

wherein each R2 is independently H or C₁₋₆ alkyl that may bestraight-chain or branched; and Z is —OH or —NH₂.
 17. The method ofclaim 16 wherein the polyolefin comprises an ethylene-acrylic acidcopolymer.
 18. The method of claim 16 wherein the carboxyl functionalpolymer comprises an ethylene-acrylic acid copolymer.
 19. The method ofclaim 16 wherein the carboxyl functional polymer comprises acrylic acid,methacrylic acid, or a copolymer thereof.
 20. The method of claim 16wherein the ultraviolet light absorbing compound contains abenzotriazole group.
 21. The method of claim 16 wherein the ultravioletlight absorbing compound contains a benzophenone group.
 22. Aconformable marking sheet comprising: (a) a top polymeric film layerhaving glass microspheres and skid resistant particles partiallyembedded therein, the film comprising a polyolefin and the ultravioletlight absorbing oligomer of claim 1 ; (b) a base layer comprising adeformable thermoplastic polymer and a nonreinforcing mineralparticulate; (c) a pressure sensitive adhesive layer; and (d) a releaseliner.
 23. An enclosed-lens retroreflective sheeting comprising a layerof lenses anchored in a binder layer, a specularly reflective layerunderlying the lenses, and a top layer comprising a polymeric film, saidfilm comprising a polyolefin and the ultraviolet light absorbingoligomer of claim 1 .
 24. A reflective sign comprising theretroreflective sheeting of claim 23 .